1. Field of the Invention
The present invention relates to a metalized film for constructing capacitors as well as a process for constructing capacitors from said film.
2. Description of the Prior Art
Metalized dielectric flexible film based capacitors are generally formed by winding individual capacitors or by stacking said metalized films so as to form a master capacitor then in cutting said master capacitors up into individual capacitors. Different known techniques for constructing these capacitors are described for example in French Pat. Nos. 879 280, 1 051 464, 1 051 465, 903 040 and 2 011 553. The metalized plastic material film is generally wound or stacked by superimposing two metalized dielectric films one having an unmetalized margin at one of its edges and the other an unmetalized margin at the other edge. Thus, the lateral sides of said capacitors may then be joined by a schoop process to one of the edges of the sides of the metalized layers or electrodes of even rank and to the other side of the metalized layers or electrodes of uneven rank.
Although this technique is advantageous, a certain number of disadvantages are noted related to the presence of air between the layers thus stacked. In the case of wound capacitors, the air layers present in the capacitor modify the capacity thereof in a way which is difficult to control and requires the winding space to be reduced so as to obtain a precise capacity value. In the case of capacitors of the stacked type obtained by cutting up from a master capacitor, an absence of homogeneity of said master capacitors may be noted, those situated under the stack being more compact than those situated at the top of the stack, which also causes a variation in capacity per volume element.